Does anyone have an idea on the best way to time stamp an arduino sketch that contains a data packet which is to be read out using a java IDE (IntelliJ) for graphic visualization of the packet. I tried declaring the time variable on the arduino section but having problem unpacking the unsigned long variable in java. Below is a snippet of the arduino code.

             unsigned long codeTime = 0; //The time the sketch takes to execute
             uint16_t dataArray[1]; // a variable to hold both sensor data

         void setup(){
              Serial.begin(9600);
              Serial1.begin(9600);
          }
         void state1(){
             if (Serial1.available()){
                    while (Serial1.available() > 0){
                 codeTime = millis(); //using the millis() instead of micros()
                 dataArray[0] = codeTime;
                 int newByte = Serial1.read(); // read in the first byte
                 dataArray[1] = newByte;
                 Serial1.write((uint16_t*)dataArray, sizeOf(dataArray));
                 }
               }
              }

            void loop(){
                   state1();
                   Serial1.flush();  //clear the serial port 
                   delay(100);
                }
                

The question now is how do i unpack the data in java to ensure that the time variable (unsigned long time variable is well unpacked in the correct order)????. The second variable i could easily unpack in java as

              int variable1 = variable2 >> 8; //as it is a 16 bit integer I shifted
                                              // the msb/lsb accordingly
              variable1 = (variable1 | variable2);  // and finally casting it.